Aiming at the problems of traceability data differentiation between upstream and downstream blockchains, difficulties in fine-grained sharing, and data privacy protection existing in the existing supply chain of fruits and vegetables and agricultural products, an attribute-based cross-chain traceability access control model of fruits and vegetables supporting heterogeneous multi-chain was proposed by analyzing the business processes of various links in the supply chain of fruits and vegetables and agricultural products, and in the context of fruit, vegetable and agricultural products quality and safety traceability scenarios. The model used relay chain-based cross-chain technology to standardize cross-chain information to achieve cross-chain communication between heterogeneous multi-chains, and combined the cross-chain traceability requirements of fruits and vegetables with the attribute-based access control (ABAC) model to achieve flexible and fine-grained access control on data resources. In order to verify the effectiveness of the model, BitXHub relay chain technology was used to realize cross-chain data access in the heterogeneous chain composed of Hyperledger Fabric and Ethereum, and the attribute-based access control process was implemented in the cross-chain contract, so as to construct a prototype system of the cross-chain access control model for fruit and vegetable traceability. The system test results showed that the average maximum value of the sending rate of the relay chain for processing cross-chain transactions was about 600t/s and 400t/s, respectively, and the policy determination time did not fluctuate greatly with the increase of the number of policies, and was basically stable at about 2000ms, which was able to satisfy the needs of the fruit and vegetable supply chain for the differentiated and fine-grained sharing of cross-chain data among heterogeneous blockchains, and also ensured the data sharing process of the data privacy.